wang@ubuntu:~/wcycode/demo$ nm a   
08049f20 d _DYNAMIC
08049ff4 d _GLOBAL_OFFSET_TABLE_
0804850c R _IO_stdin_used
         w _Jv_RegisterClasses
08049f10 d __CTOR_END__
08049f0c d __CTOR_LIST__
08049f18 D __DTOR_END__
08049f14 d __DTOR_LIST__
08048520 r __FRAME_END__
08049f1c d __JCR_END__
08049f1c d __JCR_LIST__
0804a014 A __bss_start
0804a00c D __data_start
080484c0 t __do_global_ctors_aux
08048380 t __do_global_dtors_aux
0804a010 D __dso_handle
         w __gmon_start__
080484ba T __i686.get_pc_thunk.bx
08049f0c d __init_array_end
08049f0c d __init_array_start
08048450 T __libc_csu_fini
08048460 T __libc_csu_init
         U __libc_start_main@@GLIBC_2.0
         U __printf_chk@@GLIBC_2.3.4
0804a014 A _edata
0804a01c A _end
080484ec T _fini
08048508 R _fp_hw
080482dc T _init
08048350 T _start
0804a014 b completed.7021
0804a00c W data_start
0804a018 b dtor_idx.7023
080483e0 t frame_dummy
08048430 T main
08048410 T print_hello